Bereshis 25:19

19 And these are the toldot of Yitzchak ben Avraham: Avraham fathered Yitzchak;

Bereshis 25:19 Meaning and Commentary

Genesis 25:19

And these [are] the generations of Isaac, Abraham's son
Moses, having given the genealogy of Ishmael and his posterity, returns to Isaac, the other son of Abraham, with whom and his children the following part of his history is chiefly, if not altogether concerned: Abraham begat Isaac;
for the further confirmation of his being his proper legitimate son this clause is added.

Bereshis 25:19 In-Context

17 And these are the years of the life of Yishmael, an hundred and thirty and seven shanah; and he breathed his last and died; and was gathered unto his people.

18 And they dwelt from Chavilah unto Shur, that is near Mitzrayim, as thou goest toward Assyria; they took their place east of their brethren.

19 And these are the toldot of Yitzchak ben Avraham: Avraham fathered Yitzchak;

20 And Yitzchak was arba’im shanah when he took Rivkah as his wife, the bat Betuel the Aramean of Padan Aram, the achot Lavan the Aramean.

21 And Yitzchak davened to Hashem on behalf of his isha, because she was barren; and Hashem was entreated of him, and Rivkah his isha conceived.